Controlling the synthesis gas composition of a steam methane reformer

Abstract

Systems and methods for processing a methane rich producer gas are provided in which the producer gas is preferably produced via steam-hydrogasification. The product stream from the steam-hydrogasification is then subjected to autothermal reforming, steam is removed after the reforming step via condensation, and sulfur impurities are subsequently eliminated. In most preferred aspects, the process pressure is substantially maintained throughout all steps, typically in a range of 150 psi to 500 psi.

The invention claimed is: 
     
       1. A method of processing a methane containing gas from a steam-hydrogasification reactor to thereby form a syngas, comprising:
 feeding hydrogen and an aqueous slurry of water and a carbonaceous material to a steam-hydrogasification reactor; 
 operating the steam-hydrogasification reactor at a pressure and under conditions effective to form steam from the slurry to thereby, with the hydrogen, form a methane-containing product gas; 
 feeding the methane-containing product gas into an autothermal methane reformer, and subjecting the methane-containing product at the pressure to a reforming reaction to thereby form a hydrogen-enriched product gas; 
 condensing steam from the hydrogen-enriched product gas at the pressure to thereby form a dehydrated hydrogen-enriched product gas; and 
 removing sulfur compounds at the pressure from the dehydrated hydrogen-enriched product gas to thereby form the syngas. 
 
     
     
       2. The method of  claim 1  wherein the pressure is between 150 psi and 500 psi. 
     
     
       3. The method of  claim 1  wherein the step of operating the steam-hydrogasification reactor is performed at a temperature of between 700° C. and 900° C. 
     
     
       4. The method of  claim 1  wherein the step of autothermal reforming is performed at a temperature of between 550° C. and 750° C. 
     
     
       5. The method of  claim 1  wherein the step of autothermal reforming further comprises a step of feeding oxygen to the autothermal methane reformer. 
     
     
       6. The method of  claim 1  further comprising a step of heating the dehydrated hydrogen-enriched product gas before the step of removing the sulfur compounds. 
     
     
       7. The method of  claim 1  wherein the step of removing the sulfur compounds comprises use of metal oxide sorbents. 
     
     
       8. The method of  claim 1  further comprising a step of subjecting the syngas in a Fisher-Tropsch reactor to a Fischer-Tropsch reaction to produce a fuel product and a tail gas, and recycling at least a portion of the tail gas to the steam-hydrogasification reactor. 
     
     
       9. The method of  claim 8  wherein all of the hydrogen fed to the steam-hydrogasification reactor is internally generated and obtained from the syngas and the tail gas. 
     
     
       10. The method of  claim 8  wherein heat from the Fischer-Tropsch reaction is provided to at least one of the autothermal methane reformer and the steam-hydrogasification reactor. 
     
     
       11. The method of  claim 8  wherein hydrogen and heat from the Fischer-Tropsch reaction is provided to the steam-hydrogasification reactor. 
     
     
       12. The method of  claim 1  wherein all of the hydrogen fed to the steam-hydrogasification reactor is internally generated and obtained from the syngas. 
     
     
       13. The method of  claim 1  wherein steam required in the reforming reaction is obtained from the slurry. 
     
     
       14. The method of  claim 1  wherein the syngas has a hydrogen to carbon monoxide ratio of 3:1. 
     
     
       15. The method of  claim 1  further comprising a step of changing at least one of a water content of the slurry and a quantity of the hydrogen fed to the steam-hydrogasification reactor to thereby control a hydrogen to carbon monoxide ratio of the syngas.